The present invention pertains to medical nuclear magnetic resonance scanners, particularly as employed during magnetic resonance imaging (MRI) procedures.
Since the invention of the medical nuclear magnetic resonance (NMR) scanning technique by Dr. Raymond Damadian, as set forth in U.S. Pat. No. 3,789,832, this technique has been widely adopted in the medical arts. Medical NMR scanning requires creation of a substantial constant "primary" magnetic field passing through the patient's body. Additional "gradient" magnetic fields varying with time typically are superimposed on the primary field. The patient is exposed to radio frequency electromagnetic waves which also vary with time in particular patterns. Under the influence of the magnetic fields and the radio waves, certain atomic nuclei within the patient's tissues resonate and emit further radio waves. By known mathematical techniques involving correlation of the magnetic field patterns in use at various times with the radio frequency waves emitted, it is possible to determine physical condition at various locations within the patient's body. This information typically is displayed as an image with intensity corresponding to the concentration and/or physical state of certain nuclei of interest. The concentrations or physical state of different substances ordinarily differ for differing kinds of tissues within the body, and also permits the physician to see abnormalities, such as tumors, within the body. Accordingly, MR imaging techniques have been widely adopted by physicians.
Present day magnetic resonance scanners typically possess a patient handling system which is in close proximity to an aperture of the magnet responsible for generating the primary magnetic field. The patient handling system is used to position the anatomical region of interest to be investigated during an MRI procedure, into a portion of the primary magnetic field referred to as the imaging volume.
Following the completion of the scan protocol, the patient is removed from the magnet and unloaded from the patient handling system, and preparations for the next patient are made. Such a series of events is repeated for each patient to be subjected to an MRI procedure.
Magnetic resonance imaging practiced in such a way limits the utilization of the magnetic resonance scanner since only one patient at a time is submitted to a magnetic resonance imaging procedure. Such practices contribute to the high cost of medical care and slow the dissemination of this valuable diagnostic tool.
It is the objective of this invention to described approaches which improve the utilization of magnetic resonance scanners by multiplexing patient processing in order to enhance patient throughput.